Paper-making process



Patented Feb, 21, 1933 UNITED STATES PATENT OFFICE DONALD K. PATTILLO, OF DOVER-FOXCBOET, MAINE; GEORGE E. CORSON, OF CLINTON,

IOWA; AND HERBERT L. THOMPSON, OF

NORWOOD, MASSACHUSETTS, ASSIGNORS TO CLINTON CORN SYRUP REFINING COMPANY, OF CLINTON, IOWA, A CORPORATION or IOWA PAPER-MAKING- PROCESS This invention relates to paper-making processes and especially to those processes which involve the addition to the paper stock of amylaceous bondingmaterial. The term amylaceous bonding material referred to in this invention pertains to various starches, starch conversion products, dextrines, gums and oxidized starches or derivatives thereof which upon addition to a cellulose fibre effects an'increased bonding by reinforcing or strengthening of the already hydrated or gelatinized fibres.

It is one of the objects of this invention to provide an improvement in paper-making processes by which a greatly increased retention of the amylaceous bonding material is secured over what is possible in the papermaking processes as now practiced.

This increased retention of the amylaceous bonding material results in a better paper product, and as applied to paper it results in a paper which has an increased bursting and tensile strength, a greater folding endurance, greater tearing resistance, improved sheet formation, improved surface finish, decreased porosity, increased density, increased opacity, increased dielectric strength, decreased elongation, decreased formation of pin-holes, increased fibre hydration or gelatinization and increased twisting strength, increased wet strength, decreased absorptive capacity and increased flexibility besides other improved characteristics.

The terms paper or paper product as referred to in this invention pertains to those cellul'osic products formed ina continuous web by any of the generally accepted methods of manufacture, as for example, writing, bond, ledger, cover, book, tissue, wrapping, coating, paper boards, in its many modifications and forms, insulating paper, twisting, roofing and saturating felts, composition and wall boards, and, in fact, any paper or paper board or specialty product in the many forms in which these types of products are produced.

According to the present practice it is customary to add the amylaceous bonding material to the beater. Experiments have shown that when the amylaceous bonding 1931. Serial No. 532,990.

material is added to the paper stock in the beater there will result a relatively low retention of the bonding material in the finished product. In fact, this retention varies from J 10% to 40%, the remainder of the bonding material being lost to the process.

In a paper-making process the beater opcrates to separate the fibre bundles and to secure hydration by mechanical means. If the amylaceous bonding material is introduced into the beater the action of the beater promotes particle break down of the bonding material due to the passage of the material between the beater roll and the bed come in repeated contact with the cellulose fibres that the amount of retention secured is practically constant under a given set of conditions. y

According to the present invention the amylaceous bonding material is added to the paper stock subsequent to the beating operation but prior to the formation of the paper web. Our experiments have shown that where the amylaceous bonding material is introduced in this manner there will be a very greatly increased retention of the material added, the retention in some cases being nearly 100%. Such increased retention improves the quality of the finished product in the particulars mentioned above.

By introducing the amylaceous bonding material subsequent to the beating operation ,the break down of the particles of the bonding material is avoided and consequently practically all-of said particles readily adhere to and remain attached to the hydrated or gelatinized fibres of the fibre-water mixture and thus become effective in bonding the fibres together.

Fibre-water mixture or fibre-water flow as referred to in this invention ertains to the 5 process flow of cellulose fibre rom the beater chest to the paper machine wire. Generally I the amount of cellulose in the fibre water or fibre-water flow varies from 75 pounds to 500 pounds per-1000 gallons of water. In distinction to this the return or white water flow has a much-lower fibre content, seldom exceeding 5 pounds of fibre per 1000 gallons of water. In further distinction a raw water line is that which supplies water used as 'ipke up or supply water and contains no Our work has shown that the addition of amylaceous bonding material particles by this new -process effects at improvement in the retention secured and that the same retentions are secured regardless of whether the process is in operation on an 0 en, a closed or a partially closed system. T e increased adherence of the amylaceous bondin material particles to the gelatinized fibres induces an apparent hydration or gelatinization resulting in the efiects above mentioned.

It is thus seen that this process of addition is in effect a physical-chemical combination of the amylaceous bonding particle with the hydrated or gelatinized fibre as differentiated from a mechanical combination of the disrupted amylaceous bonding material particle and the unhydrated fibre m the beater proction may be due in part or in whole to the added gelatinizing effect of the amylaceous bonding material particle or may be due in part or in whole to the effect of this particle addition on the hydrated or gelatinized fibre but we do not distinguish between an actual cellulose hydration and a combination of chemical and-ph sical cellulose hydrations and so refer tot is increased hydration as 45 an apparent added hydration of the cellulose It is thus obvious that with an increased apparent hydration of the cellulose fibre modifications. can be made in the mechanical preparati of the fibre to compensate for sible to reduce the power loadings on the J ordan engines or to reduce the time of fibre preparation in the beating engines to efi'ect noteworthy power savings in the preparation of the fibre for paper-making purposes, and yet to produce a paper equal or better in all characteristics to paper made by any prior processes.

- Our work has further shown that instead of reducing power loading on the Jordans or time of preparation in the heaters it is possible to substitute an inferior and less exess. This increased hydration or gelatiniza-' pensive fibre for the more expensive fibres used in the furnish for the reason that this added apparent hydration makes possible the production of sheets with equal or better characteristics from inferior cellulose fibre than can be produced under present practice with more expensive raw materials;

Our work has further shown that the actual amount of amylaceous bonding material retained in the finished product determines many of the physical characteristics of the paper product as discussed above. It is apparent, therefore, that the control of the amount of amylaceous bonding material in the finished product will control to a more or less degree the improved. physical characteristics of the paper produced and with a constant retention of amylaceous bonding material as in this process of addition the characteristics of the paper product can be more definitel predetermined and controlled by varylng the amount of amylaceous bonding material added in the methods above described.

This process is particularly adaptable to the manufacture of specialty papers wherein one or more characteristics of the finished product enhances the value of the paper for conversion use. It is possible by this process to more or less control any or several 0 these paper characteristics to produce a superior sheet of paper for a particular purose. P Our work has shown that if increases in the physical strength characteristics of the paper are desired we can obtain such strength increases in definite relation to the amount of amylaceous bonding material added and that by so doing we can evolve paperproducts that are not possible under present day practices. For example, the addition of amylaceous bonding material particles by this new process produces a sheet of bag pa strength 0 approximately 30%, a decreased elongation of approximately 30%, and a erhaving an increased bursting.

closer formation with the same or lower porosit-y, which characteristics contribute largely to the quality of bag paper. Under present operating practices it is not considered practical or possible to effect these changes in bag paper which are brought about by the effect of amylaceous bonding material particles in controlled amounts by the process above described Other possibilities are apparent and the above is cited as a definite example of what can be accomplished in the manufacture of paper or paper specialties.

In the manufacture of paper products on multi-cylinder machines the adhesion of the various plies or cylinder sheets is of great importance. In the ordinary process of paper, making this ply adhesion is contr lled m re or less by a control of the hydration of the cellulose fibres making up the difi'er ent cylinder sheets. It is obvious, therefore, that such adhesion will vary with difi'erent fibres used and our work has shown that in many cases ply adhesion so controlled is very unsatisfactory. This process greatly increases ply adhesion on multi-cylinder machines for reasons that with the greatly increased retention of the amylaceous bonding material particles the top and bottom surfaces of each cylinder sheet have in efl'ect a layer of gelatinized bonding particles which adhere to adjacent layers of the paper web from adjoining cylinders to effect a greatly increased bonding strength between the different cylinder sheets, which bonding strength is further increased by the action of the higher temperatures in the paper drying operation and by the subsequent compression of the paper in passing through the calendar stacks.

In some types of paper or paper board manufacture the product is made on a wet machine and the finished sheet is picked up from a make-up roll in sheet form. As the sheet of board from the wet machine is not heavy enough in itself a great many sheets are imposed on each other to form the finished product and the adhesion between the sheets is of great importance in the strength and quality of the finished board. With this process such sheet adhesion is greatly increased as we have discussed in regard to multi-cylinder machine operation.

It is a general practice today in paper mills to chlorinate the paper mill system in whole or in part for the purpose of slime prevention and sterilization of the flow and product. Our work has shown that such a chlorination process removes from the paper mill system certain organic bufi'er salts and other organic solubles which if present retard or decrease slightly the efl'ectsproduced by this process of amylaceous bonding material addition. Our work has shown, therefore, that while this process is particularly elfective in both chlorinated and unchlorinated systems the effects produced in a chlorinated system are slightly greater than those secured in an unchlorinated system. It is sometimes customary in the chlorinating process to use a combination of ammonia and chlorine and designate this sterilizing action as a chloramine process. It is apparent that the same benefits will be found in the operation of this process in a chloramine treated system as in a chlorinated system.

As stated above the amylaceous bonding material which is contemplated by this inven-v tion may be various starches, starch conver sion products, dextrines, gums and oxidized starches or derivatives thereof. The amount of any particular amylaceous bonding material or combination of these materials used In an open system process the amylaceous bonding material may be introduced into the fibre-water fiow at any desired point between the beater and the paper machine wire, that is, it may be introduced into the paper stock at the Jordan headbox, or, and preferably, at a point subsequent to the Jordan headbox.

As applied to a closed or partially-closed system the amylaceous bonding material may be introduced into the white water return flow at any point subsequent to the white water collecting box or between the paper machine wire and collecting boxbutlprior to the addition of the white water to the fibrewater flow. The addition of the amylaceous bonding material may also be made through any raw water line on either an open or closed or partially-closed system prior to its addition to the fibre-water flow.

Our work has shown that the amylaceous bonding material is best added continuously either in a dry state by means of a dry chemical feeder or in a solution or suspension form by means of suitable equipment for introducing the material in the solution-or suspension form. It is possible also to add the amylaceous bonding material semi-continuously and to compensate for the lack of continuity in feed by the proper control of the rate of feed after a lapse in feeding or by the subsequent mixing of treated and untreated cellulose fibre in a suitable chest or tank with proper agitation to produce the same effects as if the amylaceous bonding material'had been.

added in continuous flow.

We claim.

1. That improvement in the process of making paper to improve its physical characteristics which consists in mechanically hydrating the fibres by a beater operation, flowing the mixture to a paper makingmachine and adding an amylaceous bonding material to the mixture at a point between the heater and the paper making machine thereby securing an increased retention of the bonding material in the finished paper over that ob tained by adding the bonding material to the beater.

2. Thatimprovementin the process of making paper which consists in subjecting the fibre-water mixture to the operation of a beater to' hydrate the fibre, flowing. the beatertreated fibre-water mixture to a paper making machine on which the paper is made and adding to the fibre water flow continuously and in regulated quantities an amylaceous bonding material thereby securing a greater 5 retention of the bonding material and consequent improved physical characteristics in the finished aper over that obtained by adding the bontiing'material to the heater.

3. That im rovement in the process of mak- 1 ing paper w ch includes a white-water return flow delivering to the fibre-water flow at a point subsequent to the beating operation, which improvement consists in. adding to the white-water return flow an amylaceous bond- 15 ing material thereby securing an increased retention of the bonding material and conseuent improved physical characteristics in t e finished paper over that where the bond ing material is added in the beater.

'20 4. That improvement in the process of making paper which consists in'adding amylaoeous bonding material to the fibre-water flow between the heater and the paper making machine through the raw water supply line 25 thereby securing an increased retention 0 bonding material and consequent improved physical characteristics in the finished paper. testimony whereof, we have signed our names to this specification. a0 DONALD K. PATTILLO.

GEORGE E. CORSON. HERBERT L. THOMPSON. 

